1. Field of the Invention
This invention relates generally to waterbed mattresses and more specifically to that type of mattress having interior hydraulic chambers for inhibiting wave motion and for providing a controlled release of water contents.
2. Discussion of the Prior Art
Water mattresses of the past have been adapted to two general types of waterbed assemblies. In one type of assembly, upstanding hardwood side panels support the mattress which is provided with generally square corners. In another type of construction, the waterbed is provided with foam panels which may have slanted side surfaces which support the sides of the waterbed mattress. This latter type of construction accommodates a mattress having slanted sides and is commonly referred to as hybrid waterbeds.
Each of these types of mattresses has been provided with an outer bladder which is adapted to contain the water. Disposed within that bladder is a hydraulic chamber assembly having multiple chambers each adapted to inhibit wave motion and to provide a controlled release of water from the chamber into the bladder. These chamber assemblies have been constructed with floating foam panels at an upper surface and sinking characteristics at a lower surface, in order to expand the chambers within the water. Openings between each chamber and the outer bladder have provided for the passage of water into and out of the chamber as a result of its expansion and contraction. The size of these openings has contributed to the "hardness" of the mattress when a person initially sits or lies on the bed.
Each of the chambers associated with the inner assembly have been formed in a generally rectangular configuration with bottom and side surfaces joined along multiple side seams. With these individual chamber members draped over a respective chamber die, the dies have then been individually moved into proximity and overlayed with a common closure sheet. Heatsealing the closure sheet to the individual chamber members has resulted in the combined assembly. As many as sixteen individual dies and four different types of dies have been required to form the chamber assembly. With this construction it has been necessary to form an entire top seam for each of the chambers in order to limit the number of sheets contributing to each seam. For chambers in juxtaposition, this has required two separate seams running closely parallel to each other in the assembly. This unfortunate double seam construction has demanded a wide separation of the floating foam panels. As a consequence, some undesirable bending and overlapping of the foam panels has resulted.
Another of the major problems associated with this construction has been the waste of material which has resulted from the individual formation of the chamber members. For example, material waste associated with the formation of a single chamber member has been as high as twenty-five percent. But perhaps the greatest disadvantage of this construction has been the tremendous amount of labor which has been required, not only to form the individual chamber members, but to align each of those members in a separate die and to further align as many as sixteen dies for the final chamber assembly. Perhaps insignificant with respect to these major considerations is the fact that it has always been desirable in waterbed construction to limit the number and length of seams which typically form the weakest sections of the mattress.